The present invention relates to a valve for use in a respirator. It is useable as an inlet or as an outlet valve. An inlet valve is placed between the user's face and the purifying canister; the outlet valve permits exhaustion of air from the respirator and is particularly though not exclusively intended for use in a speech transmitter of the general type seen in our prior European Patent Application No. 83.304598.2 (Publication No. 101292).
The valve member in that prior disclosure was a resilient, essentially flat, plate which was, however, provided with corrugations to increase its flexibility.